1. Field of the Invention
The present disclosure relates to a semiconductor apparatus having a nitride semiconductor layer.
2. Description of the Related Art
A group-III nitride semiconductor represented by gallium nitride (GaN) has a wide bandgap, that is, gallium nitride (GaN) and aluminum nitride (AlN) are wide-bandgap semiconductors having a wide bandgap width of 3.4 eV and 6.2 eV, respectively at room temperature. In addition, the group-III nitride semiconductor is high in breakdown field intensity, and high in electron saturation speed compared with a compound semiconductor such as gallium arsenide (GaAs) or silicon (Si).
Thus, a filed effect transistor (FET) made of GaN-based compound semiconductor material has been enthusiastically developed as a high-frequency electronic device or a high-output electronic device.
The nitride semiconductor material such as GaN can provide various mixed crystals with AlN or indium nitride (InN), so that a heterojunction can be formed similarly to a conventional arsenic-based semiconductor such as GaAs. Regarding the heterojunction between the nitride semiconductors such as a heterostructure of AlGaN and GaN, high-concentration and high-mobility carriers are generated in a heterojunction interface due to spontaneous polarization and piezoelectric polarization without impurity doping. Therefore, when a transistor or a diode is made of nitride semiconductor, a high-speed operation can be performed. Furthermore, when the transistor and the diode are integrated on the same substrate, a parasitic inductance can be reduced, so that a higher-speed operation and lower-loss operation can be performed.
Thus, as a known apparatus, Non-PTL 1 listed below discloses a nitride semiconductor apparatus in which a transistor and a diode made of nitride semiconductor are integrated on the same substrate to be used for a step-up power factor correction (PFC) circuit.